Note: A severe weather area depicted in the Day 4-8 period indicates a 30% or higher probability for severe thunderstorms within 25 miles of any point.

PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.

POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears highly unlikely during the entire period (e.g. less than a 30% probability for a regional severe storm area across the CONUS through the entire Day 4-8 period).

Forecast Discussion

ZCZC SPCSWOD48 ALL
ACUS48 KWNS 230948
SPC AC 230948
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0348 AM CST WED JAN 23 2013
VALID 261200Z - 311200Z
...DISCUSSION...
A PATTERN SHIFT APPEARS LIKELY NEXT WEEK...WITH A SEVERE WEATHER
THREAT DEVELOPING OVER PORTIONS OF THE SRN PLAINS AND LOWER MS
VALLEY.
ON SAT/D4...THE ERN TROUGH WILL MOVE OFFSHORE...ALLOWING FOR A
TEMPORARILY ZONAL FLOW REGIME ACROSS MUCH OF THE CONUS. MODELS DO
INDICATE A LOWER LATITUDE SHORTWAVE TROUGH MOVING INTO THE SRN HIGH
PLAINS LATE SAT INTO SUN/D5...AND THIS SYSTEM WILL LIKELY INTERACT
WITH A MOISTENING AIR MASS TO THE S TO PRODUCE THUNDERSTORMS OVER
TX...OK...AND KS. WEAK INSTABILITY SHOULD PRECLUDE ANY SEVERE THREAT
WITH THIS SYSTEM.
AS THIS TROUGH CONTINUES EWD ACROSS THE MID MS AND OH VALLEYS...IT
WILL LOSE AMPLITUDE WHILE A LARGER TROUGH TAKES SHAPE ACROSS THE WRN
STATES. THE PASSAGE OF THE LEAD TROUGH WILL ENHANCE THE SEVERE
POTENTIAL ASSOCIATED WITH THE NEXT TROUGH BY PRIMING THE AIR MASS
WITH MID 60S F BOUNDARY LAYER DEWPOINTS ON MON/D6...A FULL DAY IN
ADVANCE OF THE LARGER TROUGH.
TIMING DIFFERENCES DO EXIST BETWEEN VARIOUS MODEL SOLUTIONS AND
ENSEMBLE MEMBERS. STILL...THE LIKELY PRESENCE OF SUBSTANTIAL WARM
SECTOR MOISTURE...AS WELL AS A BROAD AREA OF STRONG DEEP LAYER SHEAR
AND FORCING ALL SUGGEST SEVERE WEATHER IS PROBABLE. THE MAIN
UNCERTAINTY IS WHERE THE THREAT WILL INITIATE...MATURE...AND
DIMINISH. GIVEN MODEL AGREEMENT OF THE LARGE SCALE PATTERN IN A
CLIMATOLOGICALLY FAVORABLE AREA...WILL INTRODUCE SEVERE FOR TUE/D7
CENTERED OVER AR.
THIS SEVERE AREA IS LIKELY TO CHANGE SHAPE AND SHIFT IN SUBSEQUENT
OUTLOOKS AS MODEL GUIDANCE CHANGES.
..JEWELL.. 01/23/2013
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